1. CDC. Nonpharmaceutical interventions (NPIs) at school. http://www.cdc.gov/nonpharmaceutical-interventions/school/index.html . [Accessed in 20, Dec 2016].
2. WHO. Global Influenza Programme. http://www.who.int/influenza/en/ . [Accessed in 20, Dec 2016].
3. WHO. Influenza virus infections in humans. http://www.who.int/influenza/human_animal_interface/virology_laboratories_and_vaccines/influenza_virus_infections_humans_feb14.pdf?ua=1 . [Accessed in 20, Dec 2016].
4. Wallinga J, Teunis P, Kretzschmar M. Using data on social contacts to estimate age-specific transmission parameters for respiratory-spread infectious agents. Am J Epidemiol. 2006;164:936–44.
5. WHO. WHO global influenza preparedness plan. http://www.who.int/csr/resources/publications/influenza/WHO_CDS_CSR_GIP_2005_5.pdf . [Accessed in 20, Dec 2016].